Change the alpha value of the navigation bar

Question

Is this possible?

I want to change the alpha value of the navigation bar in my view controller (in an animation), but if I do self.navigationController.navigat

Answer 1

MickBraun's answer in Swift:

1. In AppDelegate.swift add these lines in didFinishLaunchingWithOptions:

   // create background images for the navigation bar
   let gradientImage44 = UIImage.imageWithColor(UIColor(red: 1.0, green: 0.0, blue: 1.0, alpha: 0.2))
   let gradientImage32 = UIImage.imageWithColor(UIColor(red: 1.0, green: 0.0, blue: 1.0, alpha: 0.2))
   
   // customize the appearance of UINavigationBar
   UINavigationBar.appearance().setBackgroundImage(gradientImage44, forBarMetrics: .Default)
   UINavigationBar.appearance().setBackgroundImage(gradientImage32, forBarMetrics: .Compact)
   UINavigationBar.appearance().barStyle = .Default
   

2. Implement convenience methods to programmatically create UIImage objects.

   class func imageWithColor(colour: UIColor) -> UIImage {
       let rect = CGRectMake(0, 0, 1, 1)
   
       // Create a 1 by 1 pixel content
       UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
       colour.setFill()
       UIRectFill(rect)
   
       let image = UIGraphicsGetImageFromCurrentImageContext()
       UIGraphicsEndImageContext()
   
       return image
   }